Photo: Jeff Harris

Daphne Miller, a physician who works in San Francisco, first laid eyes on wild chicory during a visit to the island of Crete. Miller assumed the unruly vegetation piled on her friend's kitchen counter was destined for the garbage. To her surprise, it turned out to be dinner—and a delicious one, sautéed with olive oil and garlic and finished with a twist of lemon. "Children in other parts of the world eat wild greens the way kids here eat fries," says Miller, author of The Jungle Effect: The Healthiest Diets from Around the World. "They're an essential part of the Mediterranean diet."

For many Americans, though, there's a stumbling block: our bias against plants we've been taught to regard as invasive weeds. Gardeners spend entire summers trying to eradicate dandelions, not sautéing them. But to James Duke, PhD, author of The Green Pharmacy, a perfectly manicured lawn is a wasted dining opportunity. "These are plants that our ancestors ate—that humans evolved to eat," he says.

Wild greens also rank among the world's most nutritionally potent superfoods. Of the leafy vegetables, purslane is the richest known source of omega-3 fatty acids. Dandelion greens are full of vitamin E and iron. And Miller postulates that the folate, antioxidants, and fiber in African wild greens may contribute to the low rates of colorectal cancer among West Africans, who develop the disease less than one-tenth as often as Americans. It scarcely matters which of the edible weeds you choose. "I call it the Lake Wobegon effect," says Duke. As Garrison Keillor says of his fictionalized town's inhabitants, "They're all above average."